Gas purifier and sterilizer



April 1,

1947. K; EHRGOTT GAS PURIFIER AND STERILIZER Filed Feb. 28, 1942 Emu El?INVENTOR ff I71? .E'A'EGG ATTORNEY Patented Apr. 1, 1947 GAS PURIFIERAND STERILIZER Karl Ehrgott, Baltimore, Md., assignor to West'- inghouseElectric Corporation, East Pittsburgh, Pa., a corporation ofPennsylvania Application February 28, 1942, Serial No. 432,779

3 Claims.

This invention relates to means for purifying and sterilizing gas and,more particularly, to removing atmospheric dust and other impuritiesfrom air as well as sterilizing the same by killing bacteria and thelike, said means being particularly, although not necessarily, used inthe conditioning of air which is to be breathed.

The present invention is an improvement over that'described and claimedin the Penney patent, No. 2,129,783, of September 13, 1938, relating toa precipitator in which gas is blown, first through an ionizing chamberand then through a separate precipitating chamber, a significant featureof the precipitator being that the ionizing wire is of such smalldiameter that practically utilizable ionization of suspended particlesin the gas may be obtained at a wire-charging voltage below the criticalcorona voltage, thereby limiting the ionizing current input, and ozonegeneration When the precipitator is used for cleaning air.

Such a precipitator utilizes an ionizing wire of less than 32 milsdiameter, which is a somewhat critical value near the knee of the curveexpressing the relation between critical corona voltage and wirediameter. The wire is preferably much finer than this upper limit and isdesirably a tungsten wire approximately 5 mils or less in diameter. Inorder to insure against breakage and facilitate handling of theequipment, the end supports for such fine wire should be fairl rigid andstrong, and if said wire is longer than about a foot, it should besupported at intervals along its length, say every 8 inches, in order toprotect it against vibration, breakage and excessive saggmg.

An object of my invention is to introduce bac tericidal means into sucha precipitator to sterilize the air passing therethrough, as by killingair-borne bacteria and the like.

Another object of my invention is to employ enerators of ultravioletradiation of bactericidal character, which intersect or are disposedadjacent the precipitating plates, so that they not only sterilize airpassing between said plates, but also irradiate the surfaces thereof andmaintain the same in sterile condition.

Other objects and advantages of the invention, relating to theparticular arrangement and construction of the various parts, willbecome ap arent as the description proceeds.

Referring to the drawing:

Fig.1 is a vertical, longitudinal, sectional view of one form of myinvention, the section plane being indicated at I--I in Fig. 2.

Fig. 2 is a vertical, sectional view on the plane indicated by the lineIIII of Fig. 1.

In the embodiment of my invention illustrated, air to be treated isdrawn in through the top of the precipitator cabinet ll, through aprotective screening I 2, and passes downwardly through an ionizingchamber l3 in the top of the cabinet, after which it continues andpasses through a precipitating chamber, I4. A blower I5 is providedtherebeneath for drawing the air through the apparatus. The outlet ofthe blower may either discharge the treated air near the floor, or thesame might be led away in any desired manner.

The ionizing chamber l3, in the present embodiment, comprises aplurality of ionizing units disposed transversely with respect ,to thedirection of the air flow, each unit consisting of a fine wire l6, whichis desirably spaced midway between the relatively large electrodes ll,which are preferably tubular or curved in section so that they presentconvex surfaces toward the ionizing wire. As explained in the aforesaidPenney patent, the tubular electrodes I! are grounded on theprecipitator cabinet II, and the ioniz ing wires it are suspendedbetween rigid metal end supports I8 carried by-a skeleton frame work l9which is supported by insulators 2 I.

The end supports l8 must be adequately spaced from the end walls 22 ofthe cabinet in order to provide adequate insulation. It will thus beseen that the air in the space between the end walls 22 and the supports[8 is not adequately ionized, and suitable baflle designated by thereference character 23, are therefore provided for keeping the airstream from passing over these regions of poor ionization. Unless thewires,

l6 are very short it will be usually found desirable to steady them atone or more intermediate points.

The precipitating chamber [4 consists of a large number of spacedinsulated plates 24 and grounded plates 25 disposed close together andparallel to the direction of air flow. The insu lated precipitatingplates 24 are supported by notched metal members 26 which are carried byinsulators 21. The non-insulated plates 25 are supported and spaced bymeans of notched plates 28 carried by the cabinet I I.

As explained in the aforesaid Penney patent, the ionizing wires [6 andthe insulated precipitae tor plates 24 are unidirectionally charged withrespect to the uninsulated or grounded parts. Because of the greaterspacing between each wire I6 and its associated tubular electrode ll,'ascom the negative terminals being grounded onthe frame of the cabinet II,as indicated at 32.

In order to effect sterilization of the gas or air passing through thecabinet I I, while thesame is being freed of dust and otherair-borne'particles, I provide apertures 33 and 34 in the plates 24 and25 for the reception of a desirably U-shaped generator 35 of ultravioletradiations of bactericidal character. This generator, in the presentembodiment, consists of elongated tube of vitreous material containingelectrodes 36 and 31 in end chambers thereof, and an ionizable-mediumsuch as a mixture of neon and argon with mercury vapor. The vitreousmaterial of the envelope is such that it transmits ultravioletradiations of bactericidal character, that is those between 2500 and2800 A. U., as well as some in the neighborhood of 1800 A. U. It isdesirably constructed and operated generally as described in the JamesPatent, No. 2,258,765 of October 14, 1941, or corresponds with theultraviolet discharge lamps or generators sold under the trademarkSterilamp by the Westinghouse Electric & Manufacturing 00., therebycooperating with the ionizing means in avoiding the generation of anobjectionable proportion of ozone.

For convenience inapplying the generator 35, the end walls of thecabinet H are desirably apertured, similar to the precipitator plates,and after passing the arms of the' U'-shaped generator through theapertures 33 and 34, the side wall apertures are desirably closed by arelatively shallow pan-shaped cover plate 38 at one end and a deeperpan-shaped cover plate 39 at the other end. The cover plate 39 carriessockets 4i and 42 for the generator 35, as Well as a transformer 43 toprovide power atthe proper voltage for operation thereof, power leads tosaid transformer being indicated at 44 and 45.

,In operation, gas or air entering the top of the cabinet I I, as shownby the arrows, is first ionized in the chamber l3 so as to charge theparticles which are suspended therein. The air then passes through theprecipitating chamber l4 and over the arms of the U-shaped ultra-violetgenerating device 35 where charged suspended particles become attachedto the oppositely charged precipitating plates, while it is at the sametime treated by bactericidal ultraviolet radiations, whereby it ispurified and sterilized; At the same time the surfaces of theprecipitating plates and any collected particles are maintained in asterile condition by the-ultraviolet radiations impinging thereon. Theconditioned air is withdrawn from the cabinet by the blower l5.

When the precipitator, and especially the precipitating means, becomesdirty by reason of foreign particles extracted from the air, theultraviolet generating device 35 is desirably first removed andtheremainder flushed out with a hose, after which it may be reassembled foruse.

From the foregoing disclosure it will be seen that I have not onlyprovided for removing particles :of dustland foreign'matter from gas-orair,

but have also provided for the simultaneous sterilization of said air,as well as maintaining the precipitating plates and any coating thereonin sterile condition, whereby my apparatus may be employed for airconditioning purposes in which it is desired to reduce or eliminatebacterial air infection as well as remove dust and other solid foreignmatter. g

My present invention generallyfollows the practices explained in theaforesaid Penney patent, utilizing an ionization voltage considerablylower than the critical corona voltage, this practice being madepossible by employing fine ionizing wire.

While I have described preferred embodiments of my invention, it will beunderstood that I am not limited thereto, as modifications may be madeWithin the spirit and scope of the appended claims.

I claim:

1. A gas purifying and sterilizing device comprising an ionizingchamber, a precipitating chamber, means for causing gas to flowsuccessively through first said ionizing chamber and then saidprecipitating chamber, said precipitating chamber consisting of a seriesof closely disposed, spaced plates, alternate ones of which are at apotential dilferent from that of the ionization of the flowing gas, soas to attract solid particles in the gas passing therethrough, and meansdisposed insaid precipitating chamber for generating ultravioletradiations of a bactericidal character, said means including anelongated ultraviolet transmitting envelope, said plates being aperturedand said envelope passing through said apertures so as to extendsubstantially perpendicular to the planes of said plates. in order todirect radiation on the plate surfaces to maintain the same in sterilecondition, as Well as sterilize the gas flowing therebetween.

2. A ga purifying an sterilizing device comprising an ionizing chamber,a precipitating chamber, means for causing gas to flow successivelythrough first said ionizing chamber and then said precipitating chamber,said ionizing chamber being provided with one or more i0nizing unitseach disposed transverse to the gas flow and comprising oppositelycharged electrodes, one of said electrodes being a single fine wirespaced between relatively large electrodes, said precipitating chambercomprising spaced, oppositelycharged plates lying substantially parallelto the direction of the gas flow, alternate plates being at a potentialdifferent from that of the ionizing wire so as to collect chargedparticles from the gas passing therebetween, and means disposed in saidprecipitating chamber and passing through apertures in said plates forgenerating ultraviolet radiations of a bactericidal character in orderto direct such radiations on the plate surfaces to maintain them insterilecondition and sterilize the gas passing therebetween.

v3 A gas purifying'and sterilizing device comprising an ionizingchamber, a precipitating chamber, means for causing gas to flowsuccessivelythrough first said ionizing chamber and then saidprecipitating chamber, said ionizing chamber beingprovided with one ormore ionizing units, each disposed transverse to the gas flow andcomprising oppositely charged electrodes, at least one of saidelectrodes being a single fine wire spaced between relatively largeelectrodes, said precipitating chamber comprising spaced, oppositelycharged, generally fiat electrodes lying substantially parallel to thedirection of the gas a flow and one another, means associated with theionizing chamber and the precipitating chamber for unidirectionallycharging said electrodes, said wire being charged to a voltage which isbelow the critical corona voltage and of such fineness that practicallyutilizable ionization of the particles suspended in the gas is obtained,and means disposed in said precipitating chamber for generatingultraviolet radiations, a large portion of which lie between 2500 and2800 A. U., in order that the same may be strongly bactericidal, saidmeans consisting of an elongated ultraviolet transmitting envelope, saidplates being apertured and said envelope passing through said aperturesso as to extend substantially perpen- 15 KARL EHRGOTT.

REFERENCES CITED The following references are of record in the 10 fileof this patent:

UNITED STATES PATENTS Number Name Date 2,271,792 Conant Feb. 3, 19422,218,190 Anderson Oct. 15, 1940

